Stack forming apparatus

Bodies such as nuclear fuel pellets are formed into a stack in a stacking lane and the length (or weight) of the stack is measured at intervals by a device to determine if the partly-formed stack is drifting away from the target length (or weight). Pellets are issued into the stacking zone by a selector mechanism, the input of which receives pellets from three lanes containing oversize, undersize and intermediate size pellets and the pellets issued to the stacking lane are selected under the control of microprocessor-based unit according to the extent of any drift from the target value. The pellets in lanes are derived from a common supply following segregation by a diverter mechanism controlled by unit in accordance with length/weight measurements made by measuring device. (author)